External fuel tanks are additional containers used to store fuel for aircraft, rockets, or vehicles. They are designed to increase the range or endurance of the vehicle by providing extra fuel capacity. These tanks can be jettisoned when empty, allowing the vehicle to reduce weight and improve performance. In aviation, external fuel tanks are often mounted under the wings or fuselage of an aircraft, such as the F-15 Eagle. In space exploration, rockets like the Space Shuttle used external fuel tanks to carry liquid fuel needed for launch. These tanks play a crucial role in extending operational capabilities.